package field_method66;

public class Circle {
    double r;

    public void area() {
        double pai = 3.14;
        double s =pai*r*r;
        System.out.println("面积为;"+s);

    }

    public  void area2(double pai) {
        double s = pai *r*r;
        System.out.println("面积为;"+s);

    }

    public double area3(double r,double pai) {
        double s= pai *r*pai;
        return s;

    }
}
